Studies On The Taxonomy,Community Diversity,Seasonal Dynamics Of Ladybugs In The Oasis Areas Of Northern Xinjiang (Coleoptera,Coccinellidae)

Ladybugs(Coccinellidae),as an important predatory insects,is widely distributed in the world and play an important role in the natural control of agricultural and forest pests.Endemic ladybug resources are abundant in Xinjiang,but there are still a series of problems such as unclear species composition and distribution.In this study,we investigated 28 representative habitats in 39 counties/cities in northern Xinjiang by using net capture method,and identified the community composition,species distribution,and seasonal dynamics of these habitats.The main research results are as follows:(1)A total of 8122 specimens were collected from 438 sites in northern Xinjiang from 2018 to 2020,belonging to 34 species of 5 subfamilies.The subfamily Coccinellinae had the most species(24 species),followed by Scymninae(4 species)and Chilocorinae(3 species).The dominant species were Adonia variegata and Propylea quaturodecimpunctata.In addition,seven newly recorded species from Xinjiang were also found: Scymnus folchinii,Adalia conglomerate,Coccinula sinensis,Coccinella longifasciata,Hyperaspis leechi,Epilachna insignis,Henosepilachna vigintioctomaculata.(2)Ladybug community seasonal dynamics showed that the number of individuals and groups exist obvious differences in seasonal dynamic distribution among 6 different habitats.The highest individual number(no.262 / sample/times)and species richness(20)are presented in alfalfa field,and the cotton fields are poorest with 48 / sample/time)and 4 species.According to the diversity analysis,the diversity index,richness,evenness(0.62,2.06,0.72)of shelterbelt were the highest in the whole growing season,followed by the alfalfa field(0.55,2.35,0.49),while the cotton field(0.21,0.46,0.57)was the lowest.The similarity analysis showed that the community similarity coefficient between different habitats was basically medium similarity(0.5≤q≤0.75).(3)From farmland landscape view,the species and individuals of ladybird community in wheat field,corn field and alfalfa field were abundant,with large distribution scale and high diversity level.The diversity index,richness,evenness(1.02,7.21,0.75)were all higher in Yili Valley,while those in Turpan(2.80,0.42,0.38)were lower,but the dominance index(0.57)was higher,which may indicate that there were fewer species and individuals,uneven distribution of species and unstable community in this area.(4)The species,community composition and structure of ladybugs in Yili Valley showed that there were abundant ladybug resources(19 species,43.58 individuals per survey site)in alfalfa fields.The number of species in beet field and peanut field was much less.The richness,evenness,and diversity index(1.01,6.27,0.75)were higher in Yining County than in Horguos City(0.48,3.28,0.48),but the latter’s dominance index(0.53)was higher,which indicated that there might be fewer species and individuals,uneven species distribution and unstable ladybug community in this region.